1. Field of the Invention
This invention pertains to a device which, when attached to a rope, can be easily moved along the rope using one hand, but can jam the rope against movement when a certain portion of the device is constrained from movement and an end of the rope is pulled with respect to the device. Within the field of rock climbing, this device meets a currently unmet need for a back-up safety device for solo climbing activities. With the addition of a cord, the device can also be used in place of many of the safety friction knots used in the field of rock climbing. Certain embodiments of the device also provide the functionality of a standard simple belay and rappel device. Certain embodiments of the device also function as an auto-locking belay device. The device can be produced to accommodate either one or two ropes.
2. Description of Prior Art
In the sport of rock climbing, a belay device is used to protect a climber from injury in the case of a fall. Generally the climber wears a harness to which one end of a rope is attached. The rope passes through a belay device that is often attached to the harness of another person, the “belayer”. The belayer operates the belay device and typically remains at a stable point while the climber ascends. When the climber is “lead” climbing, the climber drags the rope up the rock as he ascends. At various points during the ascent, the climber clips the rope into metal loops (carabiners) that, in turn, are attached to the surface of the rock. When the climber is “top-rope” climbing, the rope extends down toward the climber from above. In the case of lead climbing, the belayer feeds out rope as the climber ascends. In the case of top-rope climbing, the belayer takes in rope as the climber ascends. In either case, if the climber falls, the belayer must grasp the rope securely by means of the belay device. The fall is therefore stopped by means of the belay device and the climber comes to rest suspended from above by the rope. Thereafter, the belayer may gently lower the climber to the ground by operating the belay device so as to gradually release tension on the rope. Anyone experienced in rock climbing is familiar with this practice and with the various forms of belay devices.
The simplest, most common, belay device is made up of a solid piece with one or two oval passages and a containment loop. The version with two oval passages can handle two ropes simultaneously. In use, a loop of rope is threaded through the oval passage and a carabiner is clipped through the rope loop as well as the containment loop. The carabiner is also attached to the harness of a belayer. When a climber falls, the rope passing through the oval passage causes the carabiner to be pulled against the surface of the solid piece. The oval passage opening is dimensioned so as to constrain the rope when the carabiner is pulled against it. These devices provide friction to slow the rope, but they all require the belayer to provide additional braking force in order to stop the rope. An example of this simple type of belay device is the ATC Climbing Belay Device by Black Diamond Equipment Ltd. of Salt Lake City, Utah.
Another class of belay devices, auto-locking belay devices, generally consists of relatively more complicated designs, often with moving parts, which have the benefit of requiring no action on the part of a belayer in order to stop a fall. An example of this class of auto-locking devices is found in U.S. Pat. No. 5,577,576 to Petzl et al. which has been commercially introduced as the GriGri Climbing Belay Device by Petzl of Crolles, France. A negative aspect of most of the devices in this class is the fact that the belayer, when required to feed out rope rapidly to the lead climber, must temporarily override the locking function of the device. If a climber falls at this moment, the belayer must release the override of the locking function, otherwise the climber will continue to fall. Another negative aspect of this class is that most auto-locking belay devices on the market will accommodate only one rope, rendering them unsuitable for dual-rope climbing and dual-rope rappelling activities.
One sub-class of auto-locking belay devices consists of devices produced specifically for solo lead climbing in which the climber climbs alone without the assistance of a belayer. In solo lead climbing, the climber anchors a rope at the bottom of the climb and attaches the belay device directly to his harness. As the climber ascends, the free side of the rope is pulled through the belay device by the anchored side of the rope. The climber periodically clips the anchored side of the rope to the rock surface. A commercial example of a belay device for solo lead climbing is the Soloist produced by Wren Industries of Grand Junction, Colo. A very significant negative aspect of many of these devices, including the Soloist, is the fact that, although they will catch a climber if he falls in the upright position, they will not catch a climber if he falls upside down. Because of this danger, producers of these devices recommend that the devices be backed-up by a series of loop knots spaced apart along the free end of the rope, the knots being large enough to catch against the device rather than be pulled through the device. Although adding one element safety, this method of backing-up the device greatly complicates the climbing activity and can, in fact, introduce an element of danger. Each loop knot has to be untied as it reaches the device in order for the rope to continue to feed through the device. On most climbs, a climber periodically can free one hand for this knot untying activity but can almost never free both hands. It is very difficult to untie these knots with only one hand and at times it is risky to even free one hand from the rock surface in order to untie a knot.
A recent new type of belay device, found in U.S. Pat. No. 6,681,891 to Richard et. al., combines the functionality of a simple belay and rappel device with a rope jamming function. Unlike the subject invention, in order to invoke the rope jamming function the device must be fixedly attached to the rock surface in a specific orientation. When anchored in this specific orientation, the device will jam the rope when the rope is pulled in one direction but will not jam the rope when it is pulled in the opposite direction.
Within the sport of rock climbing there are a variety of friction knots for safety back-up and self rescue applications including the Prusik knot, the Bachman knot, and the Klemheist knot. All of these friction knots contain a cord that wraps around the climbing rope at one end and is anchored to a fixed point at the other end, usually by a snap hook such as a carabiner. These knots allow the rope to move through them if the knot is held while the rope moves, but lock the rope against movement if the knot is released. Once the knot is released it tends to move along with the movement of the rope. Tension is caused by the rope against the knot as the knot is pulled away from its anchor point and this tension causes the knot to tighten thus stopping the movement of the rope. Unfortunately, none of these types of knots can form a suitable safety back-up for the belay device used in solo climbing activities because, since the belay device moves along with the climber, there is no suitable fixed anchor point. If the climber were to anchor the knot to himself, the anchor location would be too close to the belay device itself to be suitable for this particular application.
The devices of the prior art, including those mentioned above, do not disclose, teach or illustrate the unique structure, function and advantage of the subject Simple Climber's Multi-Tool.